The present invention relates to silicone caulking compositions resulting from the incorporation of a nonsiliceous filler, such as calcium carbonate, into a silicone emulsion and the employnent of an orthosilicate stabilizer, such as a neopentylorthosilicate.
Prior to the present invention, as shown by M. G. Elias et al., U.S. Patent 4,427,811, anionically stabilized silicone emulsion were often aged for several weeks prior to theaddition of a nonsiliceous filler. However, the resulting filled caulk showed a loss in properties if allowed to agge before water was removed. A.E. Freiberg, U.S. Patent 4,608,412, found that if a silicone caulk, consisting of an anionically stabilized silanol-terminated polymer, dialkyltindicarboxylate, an alkylorthosiicate, and an inert filler, also incorporate 2-amino-2-methyl-1-propanol, the resulting caulking resisted gelation upon aging.
The present invention is based on the discovery that shelf stable curable silicone caulking materials also can be prepared by initially anionically polymerization agent as a surfactant, to produce an aqueous emulsion. The pH of the emulsion is adjusted to a range of about 9-11, and combined with a nonsiliceous filler, a tin catalyst, a cross-linking agent, and an effective amount of a cross-linker as defined hereinafter, resulting from the reaction of neopentyl alcohol, and tetraalkoxysilane.